Laryngeal Mask Airway (LMA Classic)
Question 1 A 48-year-old woman with rheumatoid arthritis presents for arthroplasty of two MCP joints of her left hand. The surgeon estimates the surgery will take about 1 hour and 45 minutes. The patient's height is 157 cm and she weighs 82 kg. She has a history of gastroesophageal reflux, with symptoms well controlled on a protein pump inhibitor. Her other history is significant for steroid-induced diabetes that is well controlled with oral hypoglycemic agents. Physical examination reveals good mouth opening, but very limited neck extension, a large tongue and Grade III Mallampati view. Concerning placement of the LMA, which of the following uses of the LMA best applies in this patient? a. Diabetes is an absolute contraindication. b. Good placement of an LMA may not be straightforward. c. Placement of an LMA requires neck extension. d. History of reflux disease is an absolute contraindication. e. Surgery duration greater than 1 hour is an absolute contraindication. Answered: b. Good placement of an LMA may not be straightforward. ________________________________________ Question 2 Which of the following represent (a) relative contraindication(s) to use of an LMA? a. Failed intubation b. Inability to ventilate with a mask c. History of obstructive sleep apnea d. Thoracic surgery e. Anesthesia for inguinal hernia repair Answered: d. Thoracic surgery ________________________________________ Question 3 What are the maximum recommended inspiratory pressure and tidal volume during positive-pressure ventilation using an LMA? a. 30 cm H2O and 8 mL/kg, respectively b. 20 cm H2O and 8 mL/kg, respectively c. 20 cm H2O and 10 mL/kg, respectively d. 30 cm H2O and 10 mL/kg, respectively e. None of the above. Answered: d. 20 cm H2O and 8 mL/kg, respectively ________________________________________ Question 4 A 48-year-old woman with rheumatoid arthritis presents for arthroplasty of two MCP joints of her left hand. The surgeon estimates the surgery will take about 1 hour and 45 minutes. The patient's height is 157 cm and she weighs 82 kg. She has a history of gastroesophageal reflux, with symptoms well controlled on a protein pump inhibitor. Her other history is significant for steroid-induced diabetes that is well controlled with oral hypoglycemic agents. Physical examination reveals good mouth opening, but very limited neck extension, a large tongue and Grade III Mallampati view. The patient has an uneventful surgery, but she calls the anesthesia service 3 days later to report an increasing sore throat and problems swallowing. She states that she does not have a fever. Which of the following actions is the most appropriate next step? a. Saline rinses and throat lozenges for comfort. b. Corticosteroids to decrease inflammation c. Examination for signs of laryngeal trauma or retropharygeal abscess. d. No further action is required e. Antibiotics for infectious pharyngitis is developing. Answered: c. Examination for signs of laryngeal trauma or retropharygeal abscess. ________________________________________ Question 5 While inserting the LMA or insufflating the cuff, significant resistance is encountered. What are possible reasons? a. Obstruction by the relaxed tongue b. The LMA may have folded back on itself during insertion c. The LMA may be inserted too far d. All of the above e. None of the above Answered: d. All of the above ________________________________________ Question 6 A 48-year old-woman with rheumatoid arthritis presents for arthroplasty of two MCP joints of her left hand. The surgeon estimates the surgery will take about 1 hour and 45 minutes. The patient's height is 157 cm and she weighs 82 kg. She has a history of gastroesophageal reflux, with symptoms well controlled on a protein pump inhibitor. Her other history is significant for steroid-induced diabetes that is well controlled with oral hypoglycemic agents. Physical examination reveals good mouth opening, but very limited neck extension, a large tongue and Grade III Mallampati view. The surgery proceeds uneventfully after induction of anesthesia and placement of an LMA. The patient is noted to be breathing shallowly, and arterial oxygen saturation has fallen slightly (95%). The anesthesiologist considers instituting positive pressure ventilation to support respiration on the LMA. Which of the following outcomes from positive pressure ventilation best applies to this patient? a. Positive pressure ventilation is contraindicated. b. Aspiration risk is increased using positive pressure ventilation. c. Improved arterial oxygenation and decreased CO2 retention. d. Requires the administration of neuromuscular blocker. e. Pressure of 30 cm H2O is necessary. Answered: c. Improved arterial oxygenation and decreased CO2 retention. ________________________________________ Question 7 A 48-year-old woman with rheumatoid arthritis presents for arthroplasty of two MCP joints of her left hand. The surgeon estimates the surgery will take about 1 hour and 45 minutes. The patient's height is 157 cm and she weighs 82 kg. She has a history of gastroesophageal reflux, with symptoms well controlled on a protein pump inhibitor. Her other history is significant for steroid-induced diabetes that is well controlled with oral hypoglycemic agents. Physical examination reveals good mouth opening, but very limited neck extension, a large tongue and Grade III Mallampati view. The patient undergoes IV induction and placement of a #4 LMA. A few minutes after incision, "crowing" sounds are heard from the LMA. Which of the following actions is the most appropriate next step? a. As long as good air exchange is happening, nothing should be done. b. Replace with a #5 LMA. c. The patient should be examined for signs of significant obstruction. d. The LMA should be repositioned. e. The anesthetic should be deepened. Answered: c. The patient should be examined for signs of significant obstruction. ________________________________________ Question 8 During use of an LMA with positive-pressure ventilation, which of the following is/are true? a. Improvement in ventilatory pattern and CO2 elimination may result b. Significant increases in minute ventilation have been demonstrated c. Gastric insufflation is common up to pressures of 25 cm H2O d. When patients are properly selected, aspiration rates are still higher with LMAs than endotracheal tubes e. A and B Answered: e. A and B ________________________________________ Question 9 Which of the following are indications for use of an LMA? a. Airway management for general anesthesia with spontaneous ventilation b. Rescue airway after failed intubation c. Inability to extend or rotate the cervical spine due to trauma or congenital abnormalities d. Patients who are 14 weeks pregnant e. A, B, and C Answered: e. A, B, and C